/Engine/Source/Runtime/AudioMixer/Public/AudioMixerSubmix.h
This sets up the ambisonics positional data for speakers, based on what new format we need to convert to.
void SetUpSoundfieldPositionalData ( const [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [Audio::FMixerSubmix](API\Runtime\AudioMixer\FMixerSubmix), ESPMode::ThreadSafe > & InParentSubmix )